The book opens with a sly and somewhat snarky introduction that, like Tolkien's, recounts the events of the (unwritten) counterpart to The Hobbit, in the process introducing the reader to the boggies, a "short and squat, and yet dull" people no longer much seen in the world. It briefly summarizes the adventures of the boggie Dildo Bugger after he was recruited by a "discredited Rosicrucian" named Goodgulf Greyteeth, and how he found the One Ring in the lair of a creature known only as Goddam.
It then launches into the story proper, which covers Dildo's nephew Frito being shanghaied into taking the One Ring to the elven land of Riv'n'dell by Goodgulf. Taking his man-servant Spam Gangree, and being forced to take twin morons Moxie and Pepsi Dingleberry (again by Goodgulf), the four set out for the elven lands.
Forced to take a path through the "haunted" Evilyn Wood due to a pig-riding menance, the four run into a hickey tree, which strips them and threatens to kiss them to death. However, they are saved by the drug-addicted Tim Benzedrine, who takes them to his home to meet his wife Hashberry. He gives them strange pills, which the boggies take before passing out. They awaken to resume their journey, with more of the strange pills in their possession.
The four arrive in the town of Whee, entering by feeding the guards the strange pills. Arriving at the Goode Eats & Lodging tavern, they meet up with Arrowroot there, and then barely escape a surprise attack by the wicked Nozdrul (mainly due to Arrowroot's clumsiness making the Nozdrul have laughing fits). A hasty contrivance by the elf Garfinkel manages to enable their escape, and the group rides to Riv'n'dell.
There, through a series of insults and bravado, the members of the Fellowship (Frito, Goodgulf, Spam, Moxie, Pepsie, Arrowroot, Bromosel, Gimlet and Legolam) are unwillingly nominated to destroy the One Ring. After a brief journey, the Fellowship finds itself lost, with no choice but to enter the abandoned Mines of Doria. After losing (i.e. sacrificing) Goodgulf to a Ballhog in the depths of Doria, the Fellowship then enter the elven lands of Lornadoon, where they receive shelter and less-than-helpful gifts from Cellophane and Lavalier, the leaders of the land.
Shortly afterwards, the Fellowship almost immediately disintegrates in the most spectacular fashion possible, with Bromosel dying. Even as its members scatter they are pursued by the forces of Sorhed, including the dread pig-riding Nozdrul and the crude and vicious Narcs.
Arrowroot, Legolam, and Gimlet find themselves captured by, and then caught up in the troubles of, the Riders of Roi-Tan. An entire nation of German stereotypes on sheep-back, the Roi-Tanners provide Arrowroot with a romantic interest in their princess Eorache. Goodgulf returns, and they plan to assault Isinglass, home of the "evil" Serutan. However, their initial attack utterly fails, although Arrowroot's royal lineage is revealed to Eorache.
Moxie and Pepsi find themselves, after a quick escape from some narcs, in the forest. They soon meet up with Birdseye, leader of the Vee-Ates, who also is planning to wage war on Serutan. The two boggies accompany the Vee-Ates, and re-unite with Arrowroot and his companions after the Vee-Ates finish off Serutan.
Meanwhile, Frito and Spam slowly wend their way to the borders of the dark realm of Fordor, avoiding numerous dangers, not the least of which is Sorhed's ex-wife, Schlob. They also meet up with Goddam, who it turns out is an extremely talkative clown, which just annoys them.
Goodgulf, after sending the rest of the companions to gather reinforcements, goes to Minas Troney, capital of Twodor, with Moxie and Pepsi. There he engineers a takeover of the government of the city by murdering the steward. After utterly failing to prepare the city for the onslaught of Sorhed's armies, they are only saved by reinforcements from the various other lands. After the battle, Arrowroot notices Eorache eyeing Farahslax, the steward's son, so he kills Farahslax in private and chalks it up to wounds and unsuccessful medical treatment.
Then, in order to prove his claim to the throne of Twodor, Arrowroot agrees to march against Sorhed, over Goodgulf's (very loud) objections. However, the vast majority of his army deserts on the way, leaving only a handful to face the fearsome hordes that Sorhed has assembled.
It all ends happily when Goddam falls (i.e. is tripped) into a convenient tar pit with the Ring. Sorhed and his armies are unmade, and the boggies are rescued by a handy Deus Ex Machina in the form of the giant eagle Gwahno the Windlord. Arrowroot is hitched to Eorache afterwards, and is crowned king.
When Frito finally makes it back home, he finds that the Stye is a filthy, squalid cesspit populated by lazy ne'er-do-wells and the intellectually challenged -- in short, nothing has changed in the beloved land of his birth. Returning to the dank, moldy comfort of Bog End, he settles into a comfortable, much-anticipated retirement filled with the fulfillment of utter sloth, disgusting gluttony, and dirty Scrabble.